Behind her roles of professional bad girls and driven professionals, Helen Mirren reveals a competitive nature, a gypsy spirit and a fondness for hugging trees.

Here come the drunks, falling over each other, spoilting for conflict. Just past midnight on a Friday in Soho, and the drunks can see a sandwich bar ahead, still open, neon lights shining crowded with film people shooting a cop series. The drunks like the look of the place, wander in, cause trouble. They see its closed for business so they shout, “Hey, Luigi, two espressos!”, looking to stir things up, aggravate a little. And they won’t go away. “Nah,” they tell the film guys. “You clear off. We’re staying”.

Then they ask, “So what’s the film anyway?” The film is Prime Suspect 2, the sequel to an award-winning television drama that kept halt of Britain home in April 1991. The drunks aren’t impressed. Things could get a little ugly now. The film people can’t lift a finger lest they get sues, but then from behind the silver lights comes Helen Mirren, layered in pancake, angry at these bullies. This is her show, not theirs, and she tells them to clear off now or she’ll sort them out herself. “You looking for a fight?” the drunks say. “Yeah, actually,” Mirren says. And then a remarkable thing: the drunks turn away, back out into the night, cowering slightly, muttering obscenities as they go.

“I always like a punch,” Mirren muses later. “I see a fight on the street, my instinct is always to go towards. I’m pretending to be a mediator, but really I’m getting there because I want to join in, get some blood on my lips. There are many things that Helen Mirren fears, but unleashing of emotion is not one of them. Logically, those two guys would have floored her had it come to a fight, but logic has never been one of Mirren’s strong suits. To interview her – even over artichoke and salmon – is to witness the slitting of a vein: an instinctive outpouring , like tearful therapy, heart over head. An interview turns into a confessional. Out it comes, lots of stuff that she fears she “may get in trouble for later”, yet which she declines to detract.

For example, ask most actresses why they work so hard and they say: “To expand my range, to work with Meryl, or Robert, or Jodie.” With Mirren you get: “Partly I work so much because of this awful insecurity I have, but mostly it’s fear and jealousy. Professional jealousy is much worse than love jealousy. Love jealousy I can live with, but professional jealousy is a killer. I feel I’m jealous of everyone and no one’s jealous of me. It always seems that everyone else is doing the sort of work that I want. I find it almost impossible to read the Sunday papers without feeling envy. That’s why I’m so in favour of Sunday’s trading – so you’ve got something else to do but read about other people’s wonderful achievements.”

It seems that Helen Mirren has always been with us. The early Shakespeare leads, the raunchy films, the serious television stuff. Pinewood, Granada, Beeb, fringe, West End, Hollywood – a range as dazzling it must be exhausting. On and on, costume drama, rape, madness, betrayal. Much of it sears the memory: Cleopatra, Ophelia, Lady Macbeth, Extremities, Savage Messiah, The Long Good Friday, Caligula, Cal and The Cook The Thief His Wife and her Lover. “For my money she’s at the very top,” says David Hayman, the director of The Hawk, a recently completed British feature in which Mirren plays a woman who suspects her husband of being a serial killer – the mirror image of her role in Prime Suspect. “I can’t think of anyone who’s a more superlative screen performer of her generation in Britain. She’s hugely professional, on time, no tantrums, not a prima donna in any way, and she has no deep psychological hang-ups.”

And yet much of her output is lacklustre: evidence that the quality control often breaks down. She’s not a precious actor, and at times she appears to be almost blasé about her choice of roles. Possibly she works so hard because she doesn’t want to reflect too much. Maybe she just loves the cash. She says she enjoys the rewards her work brings, but hasn’t done anything just for the money. “But I think I would if I needed to. I’d do anything if I needed money.”

When we meet, Mirren is recovering from her work on The Hawk. “The British film industry… well I’m really glad we’ve got one, but sometimes I think the lack of money affects it so much. There’s only so much money you can save without its damaging the work.” Her reservations about working for British television run deeper. She works so hard, she says, and then it goes out at some crazy hour, and few of her friends get to see it. But she immediately recognized the role of Chief Inspector Jane Tennison as something else…